Baseline-free structural damage identification for plate-like structures based on two-dimensional curvature propagating flexural waves
Baseline-free structural damage identification for plate-like structures based on two-dimensional curvature propagating flexural waves
复制标题
基于二维曲率传播弯曲波的板状结构无基线结构损伤识别
DOI：
10.1016/j.jsv.2022.117098
复制
发表时间：
2022
影响因子：
4.7
通讯作者：
Kim, J.S.
中科院分区：
文献类型：
--
作者：
Zhou, Wei;Xu, Y.F.;Kim, J.S.
弯曲波的传播波形可以揭示出由损伤引起的局部异常的丰富信息，这些局部异常可用于损伤识别。然而，局部异常可能被测量噪声和波形的全局趋势的干扰所掩盖，并且它们可能只能指示损坏的大小和程度的一小部分。针对板状结构的损伤会在二维曲率传播弯曲波（2D-CPFW）中引入局部异常这一事实，提出了一种有效的抗噪声损伤识别方法。利用二维连续小波变换（2D-CWT）对2D-CPFW进行交替变换，以降低测量噪声和误差的不利影响。为了抑制2D-CPFW中的全局趋势并强化局部异常，应用了具有高阶拉普拉斯高斯函数和Teager能量算子的2D-CWT。首次研究了具有不同阶数的高斯拉普拉斯算子的二维连续小波变换抑制二维CPFW全局趋势的基本机理。研究发现，如果2D-CPFW的全局趋势可以用一个2 r− 1阶双变多项式很好地逼近，那么高斯函数的r阶拉普拉斯算子可以很好地抑制2D-CPFW在有限区间内的全局趋势.利用模态保证准则和统计准则来辅助选择高斯函数的拉普拉斯算子的阶数。提出了一种累积损伤指数，在损伤指数值较高的邻域内，可以识别损伤的位置和程度。如果一个完整的板状结构是几何光滑的，并没有质量和刚度的不连续性的材料制成的，所提出的方法不需要任何波形的完整的结构作为基线，因此，该方法可以被认为是无基线。通过两个算例验证了该方法的有效性和抗噪性。对两种不同损伤情况下的铝板进行了实验研究。算例和实验结果表明，该方法对损伤位置和损伤程度的识别是有效的，且具有较强的抗噪性。
Waveforms of propagating flexural waves can reveal plentiful information about local anomalies caused by damage, and the local anomalies can be used for damage identification. However, the local anomalies can be masked by the interference of measurement noise and global trends of the waveforms, and they may be able to indicate only fractions of the size and extent of the damage. In this paper, an effective noise-robust damage identification method for plate-like structures is proposed based on the fact that damage can introduce imminent local anomalies to two-dimensional curvature propagating flexural waves (2D-CPFW). The 2D-CPFW can be alternated using two-dimensional continuous wavelet transform (2D-CWT) to lower adverse effects of measurement noise and errors. To suppress global trends and intensify the local anomalies in the 2D-CPFW, 2D-CWT with a higher-order Laplacian of Gaussian function and the Teager energy operator are applied. The fundamental mechanism of how 2D-CWT with different orders of Laplacians of Gaussian function can suppress global trends of 2D-CPFW is investigated for the first time. It is found that the r th-order Laplacian of Gaussian function can well suppress the global trend of a 2D-CPFW within a finite interval if the trend can be well approximated by a 2 r− 1 th-order bi-variant polynomial. The modal assurance criterion and a statistical criterion are used to assist the selection of the proper order of Laplacian of Gaussian function. An accumulative damage index is proposed, and the locations and extent of the damage can be identified within neighborhoods with high damage index values. If an intact plate-like structure is geometrically smooth and made of materials that have no mass and stiffness discontinuities, the proposed method does not require any waveforms of the intact structure serving as a baseline, and therefore, the method can be considered baseline-free. Effectiveness and noise-robustness of the proposed method are investigated in two numerical examples. Two experimental investigations were conducted on two aluminum plates under different damage scenarios. Both the numerical and experimental examples verify that the proposed method is effective and noise-robust in identifying the location and extent of the damage.